Effect of Low Calcium and Vitamin D-Deficient Diet on Bones and Teeth of Mature Rats. ∗

Abstract

Twenty niale albino rats whicli had been raised to an age of 11 niontlis on an adequate stock diet were fed for 5 weeks on a control diet containing 0.462 % calcium, 0.458% phosphorus and adequate in vitamin D. Ten of the aninials were then transferred to the experimental diet which was deficient in vitamin D and contained 0.0078% calcium and 0.450% phosphorus. Calcium and phosphorus. balances were determined for each animal over 10-day periods for 220 days. The animals of the control group remained in positive calciuni ant 1 phosphorus lxilance throughout the period of observation. The animals fed the dcficieiit diet exhibited a severely negative calcium balance and a positive phosphorus balance.

The humeri and femora and the molar and incisor teeth were dissected free of soft tissue, cleaned, dried and rendered fat-free by continuous extraction with iat solvents. During the removal of the molar teeth from the jaws, it was noted, in the case of experimental rats, that the alveolar hone was soft and friable, the alveolar crest resorbed and the teeth loosened. In the control animals the alveolar bone was well calcified, the crest normal and the teeth firmly fixed in their sockets. The incisor teeth of both groups appeared equally developed and fornied. Tlie average weight of the dry fat-free incisor teeth of the two groups was not significantly different. The awragc percentage of ash in the left femora was not significantly different between the two groups of animals.

The Volume and density of the left humerus of each animal was determined, using a spcially designed pycnometer and mercury as the suspension medium. The average volume of the humeri of the experimental animals did not differ from that of the controls but the average density of the bones of the former animals was 10.8% less than that of the controls. The calcium and phosphorus contents of the left humeri, in terms of percent of the dry fat-free weight, were not significantly different between the two groups of animals.